AB0214 VALIDATION OF JOINT INDEX VECTOR FOR PATIENT WITH RHEUMATOID ARTHRITIS
Authors: I. Yoshii, S. Nishiyama
Journal: Annals of the Rheumatic Diseases (2023)

<h3>Background</h3> There are only few indices that can estimate joint involvement in both of upper and lower extremities in patients with rheumatoid arthritis (RA). <h3>Objectives</h3> One indicator can measure involvement on both upper and lower joint and large and small joint. The index developed by Nishiyama is called "Joint Index Vector", which can represent the affected state of upper and lower joints as well as large and small joints by using three-dimensional coordinates. The aim of this study is to validate the efficacy and availability in clinical practice using monitoring data from RA patients. <h3>Methods</h3> Patients who started treatment for RA after January 2016 and whose Simplified Disease Activity Index (SDAI), Health Assessment Questionnaire Disability Index (HAQ-DI), Pain Score with Visual Analog Scale (PS-VAS), and EuroQol 5th dimension (EQ5D) were monitored at each visit and Sharp/van der Heijde score (SHS) was monitored annually were included in the study. The JIV represents the joint prevalence of the upper limb in X coordinates (Vx), the joint prevalence of the lower limb in Y coordinates (Vy), and the difference in joint prevalence between large and small joints in Z coordinates (Vz) [1]. The relationship between each clinical parameter and three elements of the JIV was evaluated statistically. Each parameter was defined as the dependent factor, and the three elements of the JIV were defined as the independent factor, and correlation was examined using linear regression analysis. These procedures were performed at the first visit (BL), 1 year after the first visit (1Y), and at te last visit (LT). Additionally, the change in the HAQ score and SHS at 1Y (dHAQ and dSHS) were defined as the dependent variant, and the other parameters including the three coordinates of JIV were defined as the independent variant. Then, correlation between these parameters were statistically examined also using linear regression analysis. <h3>Results</h3> A total of 419 patients in whom 113 were male and 306 were female, were recruited in the study. Mean age at baseline was 68.1 and mean follow-up period was 65.3 months. Vx, Vy, and Vz significantly correlated with SDAI at all periods of BL,1Y, and LT. Vy significantly correlated with HAQ-DI at all periods, whereas Vx and Vy significantly correlated with PS-VAS at all periods. Vy significantly correlated with SHS at 1Y and LT. Vz significantly correlated with EQ5D at 1Y and LT. Mean dHAQ significantly correlated with age, SHS, PS-VAS, and Vz. Mean dSHS significantly correlated with Vx, Vy and annual change of Vx. <h3>Conclusion</h3> These results demonstrated that Vx, Vy, and Vz suggested significant correlation with other clinical parameters, especially Vy which represents affected joints in the lower extremities significantly correlates with important patient related outcomes. <h3>Reference</h3> [1]Nishiyama S, Sawada T, Nishino J, Tohma S. Joint index vector: a novel assessment measure for stratified medicine in patients with rheumatoid arthritis. Journal of Big Data. 2018;5(1):37. <h3>Acknowledgements:</h3> NIL. <h3>Disclosure of Interests</h3> None Declared.